Thermionic tube



Nov. 28, 1933. F. s. MCCULLOUGH 1,937,201

THERMIONIC TUBE Filed May 1, 192

INVENTOR Patented Nov. 28, 1933 Frederick S.

THERMIONIC TUBE McCullough, Edgewood, Pa., assignor to The UnionNational Bank of Pittsburgh,

Pittsburgh, Pa.

Application May 1, 1926. (Serial No. 105,965 6 Claims. .(Cl. 250-27 5)This invention relates to thermionic tubes, and. particularly to tubesfor use in radio and similar circuits.

By reason of the lack of flexibility in the con- 5 trol of thecharacteristics of thermionic tubes 'of'the usual three-elementtype, itis necessary to introduce into various circuits employing the samevarious neutralizing devices and various auxiliary devices orauxiliarycircuits, according 10 to the results which. one isendeavoringto obtain and the'type of circuit employed.

The present invention has for its object to provide a tube wherein thereis a considerable flexibility of control and wherein the characteristicsof a given tube maybe widely -varied..

The invention may be readily understood by reference to the accompanying"drawing illustrating diagrammatically preferred embodiments of 'myinvention. 1 v

In the drawing:

Figure 1 represents a vertical section through an electron dischargetube embodying one form of my invention.

Figure 2 is a view similar to Figure 1, .showing a slightly modifiedform.

' Figure 3 is a view similar toFigures 1 and 52, showing a still furthermodification.

Figure 4 is a view similar toFigure :1 showing anadditional'modification Referring to Figure 1, '2 designatesan envelopeof the kind generally employed in devices of this kind. Within the tubeis a cathode 3 which maybe of anysuitable type, either of the direct-*l'ieated type or the indirectly heated type. I have illustrated'thecathode as being of a well known indirectly heated type, having heaterwires connected thereto, which pass out of the topof the tube. Outsidethe cathode is a grid or control electrode 4, and outside of this is theplate or anode. 5. The anode 5 is preferably in the form of afcylinderand is preferably made of a magnetic material, suchas nickel. In thepreferredembodiment of my invention, the grid encircles the cathode,and. is relatively .close thereto as compared with the distance betweenthe cathode and the plate 5.

' At one, and preferably both ends of the cylindricalanode 5, arecompensating or deflector elements 6. "These are preferably in the formof metal disks having a central opening sufiiciently large for thecathode and grid to be passed therethrough without contacting therewith,but which is otherwise as close to the cathode as possible. Thesecompensating elements are out of contact with the ends of the anode orplate electrode 5, but in close proximity thereto.

In the form of the invention shown in Figure 1, the compensatingelements at the opposite ends of the anode are directly connected byaconductor 7. Leading through the envelope 2 and attached to one of thetwo deflector plates is a lead wire 8. Lead wires 9, 10 and '11 are alsoprovided in the usual manner for connection withlthe cathode, grid, andplate, respectively. 7

I have foundthat by connecting the wire 8 into various circuits indifferent ways,.that the characteristics of the tube can, be Widelyvaried, independently or in conjunction with the potentials applied tothe grid. By varying the potential on the compensatingelements, or bysuitably including it in various circuits, a new element of control isprovided, and the characteristic curve of the tube can be shifted andchanged, and the oscillations ofthe tube can be readily controlled.

In Figure 1, I have'shown an inductance, such as a periodic transformerA connected between the wire 8 and the cathode connector 9. This"arrangement is illustrative of one circuit where the compensatingelements may function with the inductance A to secure. proper tuning ofa circuit in place, for instance, of a Vernier condenser. Thisarrangement is especially applicable to a circuit using untunedradio-frequency amplification in circuits having both tuned and untunedradio. frequencyamplification, such as circuits *using' single dialtuning.-

In the form of invention shown. in Figure 2, the tube is of the samegeneral construction and for the sakeof brevity I have designated thecorresponding parts with corresponding. reference numerals.- In thisform of the invention, however, I have designated thecompensatingmernberremote from the base of the tube as 6 and havedesignated the compensating member nearest the base as 6'. The members 6and 6 are not connected, as are the members 6 in Figure 1. The member 6has a lead. wire 8 attached thereto, corresponding to the wire 8 ofFigure 1, while the member 6 is statically or inductively coupled withan external circuit. For this purpose, I have shown a capacity member 12on the inside wall of thevessel, which is connected with the member 6through a wire.- Outside the vessel over the inner capacity 12 is acapacity 13. P0-

tentials impressed on the capacity 13 from any preferred source willinduce a corresponding po- 7 connected. It will be understood that themember 13 may be included in any circuit, together with or independentfrom the circuit in which the wire 8 is connected, the circuits formingno part of the present invention. I have illustrated a battery B in thiscircuit for applying a potential to element 6. I

In the arrangement shown in Figure 3, the general construction of thetube is similar to that described in Figure 1 and correspondingreference numerals have been used to designate the corresponding parts.compensating plates at the ends of the anode have been designated 6 and6", respectively. In this view, the arrangement is generally similar tothat shown in Figure 2, but I have shownthe member 6' inductivelyconnected with the member 6" through internal and external capacitymembers 12 and 13' respectively, and the capacity 13 is connected withthe wire 8" that is coupled to the compensating plate 6" through wire80.

It will be understood that each of the forms of tubes herein describedmay have a base provided thereon as is customary with devices of thiskind. In Figure 3, I have shown such a base in sections. The base is ofthe type designed to fit standard sockets, and has four pins therein atthe terminals of the several wires 8', 9, l0'- and 11', respectively. Inview of the fact that the tube is of the indirectly heated method type,there need be only one pin in the base leading to the cathode.Consequently, the fourth pin can connect to thewire so that when thetube is fitted in a standard socket, the deflector or compensatingelements can be readily included in the circuit.

It will be understood that this arrangement may be duplicated in any ofthe forms of tubes herein illustrated.

In Figure 4, I have shown a tube 15 having a cathode 16 of theindirectly heated type, a grid 17, and a plate 18. Adjacent the ends ofthe plate and grid, preferably at both ends thereof, arecompensatingelements 19 and 20 at the bottom and top of the tuberespectively. Instead'of being in the form of a plate, these are in the'form of a plurality of'turns of wire. These turns of wire are connectedin any suitable way. I have shown them connected by a wire 21corresponding to the wire 7 of Figure 1. I

The foregoing embodiments of the invention are to be considered asmerely illustrative of various arrangements which may be employed withinthe contemplation of my invention.

The compensating elements at the opposite ends of the cylindrical anodemay be separately orjointly used to control the characteristics andoperation of the tube, and by means of these defiector or compensatingelements, very fine increments of control can be obtained andcharacteristics of the tube varied within a very wide range. Not only dothe compensating elements serve to provide an adjustable means forgoverning the action of the tube, but they effectively enclose the endsof the space within the cylindrical anode to confine the electron flowwithin this space and confine the stray discharge through the ends ofthe anode.

The invention is especially applicable to radio circuits wherein theaction of the tube must be accurately controlled, andcan be used toadvan- In this view, however, the

tage in certain types ofpower tubes, particularly those used in .powerand amplification circuits, where the signal distortion due toundesirable oscillation must be most effectively eliminated.

While I have illustrated some embodiments of my invention, variouschanges may be made in the construction and arrangement of parts and inthe disposition of the elements within the spirit of my invention andunder the scope of the following claims.

I claim as my invention: 1. An electron tube comprising an evacuatedenvelope having grid, plate and cathode electrodes and having acompensating electrode therein at one end of the grid and plateelectrodes and out of electrical contact with each and located out ofthe space between the grid and the plate but in cooperative relationthereto, said electrode being electrically separate from the grid andfrom the plate and cathode, and electrostatic means for connecting saidcompensating electrode into an external circuit with other'elements ofthe tube.

2. An electron tube having a grid, plate and cathode electrodes andhaving a compensating electrode at one end of the grid and plateelectrodes and out of direct electrical contact with each other andlocated out of the space between the grid and the plate but incooperative relation thereto, said electrode being also electricallyseparate from the grid having an electrostatic coupling with theexteriorof the tube, and comprising a plate-like element located in a planesubstantially perpendicular to the plane of the other electrodes withinthe tube.

3. A thermionic tube comprising an evacuated chamber having an anode anda cathode with a grid interposed therebetween, all of which areco-axially arranged within the tube, a, compensating element adjacentone end of the anode and in close proximity thereto, and means forinductively impressing a potential on the compensating element. 1

4. A thermionic tube having an anode .and a cathode with a gridinterposed therebetween, said elements being arranged within anenvelope, a compensating element within the envelope adjacent one end ofthe anode and in cooperative relation thereto, and means forestablishing an electrostatic coupling between said compensating elementand an external circuit.

pensating electrode at one end of the plate having an electricalcoupling to the cathode, the com-1 4 pensating electrode being in theform of a flat plate and having an electrostatic connection with theexterior of the device.

. FREDERICK s. McCULLOUGI-I.

